000
FXUS61 KLWX 220829
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
329 AM EST SUN NOV 22 2009

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER NEW ENGLAND TODAY. WEAK LOW PRESSURE
WILL DEVELOP OFF THE CAROLINA COAST MONDAY BEFORE MOVING SLOWLY
NORTHEAST PAST THE MID ATLANTIC MONDAY NIGHT INTO TUESDAY...BRINGING
RAIN. HIGH PRESSURE WILL BRIEFLY BUILD LATE TUESDAY INTO
WEDNESDAY...WITH AN UPPER DISTURBANCE BRINGING UNSETTLED WEATHER FOR
LATE IN THE WEEK.

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TWO UPPER LOWS NOTED ON THE WATER VAPOR LOOP THIS MORNING...ONE OVER
NORTHEAST PA AND THE SECOND OVER SOUTH CENTRAL MISSISSIPPI. UPPER
LOW OVER PA WILL DROP SLIGHTLY SOUTH TODAY...ALONG THE MASON DIXON
LINE. THE MISSISSIPPI LOW WILL BEGIN TO MOVE NORTHEAST AND FILL.

AT THE SURFACE...HIGH PRESSURE CENTER ACROSS THE EASTERN GREAT LAKES
WILL SHIFT INTO NEW ENGLAND. THE RIDGE AXIS SHOULD CONTINUE TO HOLD
STRONG ACROSS THE MID ATLANTIC TODAY AS LOW PRESSURE FORMS ALONG THE
GULF COAST.

NO PRECIP IS EXPECTED TODAY...BUT CLOUDS WILL BE ON THE INCREASE AS
MOISTURE GETS TRANSPORTED NORTHWARD FROM THE DEEP SOUTH. AREAS ALONG
THE MASON DIXON LINE SHOULD SEE THE MOST SUNSHINE TODAY...WITH THE
PIEDMONT AND CENTRAL SHENANDOAH VALLEY CLOUDING OVER THE EARLIEST.

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
BOTH THE GFS AND THE NAM HAVE THE SURFACE RIDGE AXIS HOLDING OVER
THE CENTRAL CWFA WHILE A SURFACE LOW EMERGES OFF THE SE COAST LATE
TONIGHT/EARLY MONDAY. BOTH MODELS HAVE SLOWED THE ONSET OF ANY
PRECIPITATION ASSOCIATED WITH THE LOW PRESSURE SYSTEM UNTIL LATER IN
THE NIGHTTIME. HAVE MADE SOME SLIGHT ADJUSTMENTS TO THE POP GRIDS
OVERNIGHT...MAINLY TO DELAY THE ONSET OF PRECIP. TEMP
PROFILES...EVEN IN THE HIGHER ELEVATIONS OF NELSON/ALBEMARLE...SHOW
ALL RAIN.

.LONG TERM /MONDAY THROUGH SATURDAY/...
MONDAY AND MONDAY NIGHT...STRONG HIGH PUSHES EAST OFF NEW ENGLAND
AND THE CAROLINA COASTAL LOW PUSHES NORTHEAST OFF THE MID
ATLANTIC...CONTINUING ELY FLOW/CAD FOR THE AREA. EXPECT MARINE
MOISTURE/RAIN/DRIZZLE TO SPREAD NORTH ACROSS THE AREA WITH EAST
FACING SLOPES HAVING THE GREATEST PRECIP POTENTIAL DUE TO
TOPOGRAPHY. DUE TO OPAQUE LOW CLOUD COVER WITH SOME RAIN...EXPECT
LOW DIURNAL RANGE...MAX-T LOW TO MID 50S...MIN-T LOW TO MID 40S
/AROUND 50F NEAR SHORE/.

TUESDAY...COASTAL LOW DEVELOPS OFF THE NEW ENGLAND COAST WITH MOIST
NELY/NLY FLOW CONTINUING LIGHT RAIN/DRIZZLE EAST OF THE BLUE RIDGE
WELL INTO IF NOT THROUGH TUESDAY. A CLOSED LOW OVER THE CENTRAL
PLAINS/MID WEST TO SPREAD SWLY FLOW ACROSS THE WESTERN RIDGES BY
TUESDAY AFTERNOON. SLIGHT INCREASE IN TEMPERATURES TUESDAY...MID 50S.

TUESDAY NIGHT AND WEDNESDAY...UPPER LOW PUSHES EAST FROM THE
CENTRAL CONUS BREAKING CAD WEDGE AND ADVECTING IN MOIST SWLY FLOW.
MORE MILD TEMPERATURES...MIN-T MID TO UPPER 40S...MAX-T MID TO UPPER
50S...PERHAPS 60F IN THE MIDDLE SHENANDOAH VALLEY WITH SOME SUNSHINE.

WEDNESDAY NIGHT AND THANKSGIVING...S/W ENERGY DIGS UPPER TROUGH INTO
THE SERN CONUS BY THURSDAY. ONE OR MORE COLD FRONT PASSAGES ACROSS
THE MID ATLANTIC BRINGING PRECIP CHANCES. AMOUNT OF MOISTURE
AVAILABLE FOR THE CWA IS UNCERTAIN. COLD AIR DOES LOOK TO FOLLOW THE
FRONT...BRINGING A COOL DOWN /TO AROUND FIVE DEGREES BELOW NORMAL
MAX TEMPS/ FOR THE LATE PART OF THE WEEK INTO THE WEEKEND.

THURSDAY NIGHT THRU SATURDAY...UPPER TROUGH AXIS PUSHES ACROSS THE
CWA...WITH COASTAL CYCLOGENESIS IN THE MID ATLANTIC A POSSIBILITY IN
THE FRIDAY TIMEFRAME. CONTINUED CHANCES OF PRECIP ACROSS THE CWA FOR
THURSDAY NIGHT/FRIDAY MORNING...ADDED RAIN/SNOW MIX FOR HIGHER
ELEVATIONS /I.E. OVER 500 FT/ EAST OF THE BLUE RIDGE WITH COOLEST
AIR OF THE MONTH. BOTH THE EURO AND GFS HAVE A LOW OVER THE NERN
CONUS BY THE WEEKEND...INDICATING UPSLOPE SNOW IN NWLY FLOW FOR THE
ALLEGHENY FRONT AND POSSIBLY RIDGES FURTHER EAST. WILL HAVE TO
MONITOR FUTURE MODELS FOR CONSISTENCY ON UPPER TROUGH.

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
PATCHY MVFR FOG IS LIKELY JUST BEFORE AND RIGHT AROUND SUNRISE THIS
MORNING. ANY FOG SHOULD QUICKLY BURN OFF AFTER SUNRISE. CIGS/VSBYS
EXPECTED TO BE VFR THROUGH THE AFTERNOON. CLOUDS WILL BEGIN TO
INCREASE EARLY THIS EVENING...BUT CIGS SHOULD REMAIN ABOVE 3 KFT
BEFORE MIDNIGHT. MVFR CIGS ARE EXPECTED AFTER MIDNIGHT AT ALL
TERMINAL SITES...WITH PATCHY MVFR FOG. SCT SHOWERS ARE POSSIBLE AT
KCHO TOWARDS 12Z MON.

ONSHORE NELY/ELY FLOW /AROUND 15 KT/ MONDAY WITH PRECIP BEGINNING BY
LATE MONDAY MORNING ACROSS THE TERMINALS. IFR CIGS/VSBYS IN
RAIN/DRIZZLE WELL INTO TUESDAY. SWLY FLOW AHEAD OF THE NEXT COLD
FRONT WEDNESDAY WITH IMPROVED AVIATION CONDITIONS. COLD FRONT/S/
WITH AN UNCERTAIN AMOUNT OF MOISTURE TO CROSS WEDNESDAY
NIGHT/THURSDAY AS AN UPPER TROUGH ENTERS THE AREA...BEGINNING A
PERIOD OF UNSETTLED WEATHER INTO THE WEEKEND. CERTAINLY PAY
ATTENTION TO SUBSEQUENT FORECASTS.

.MARINE...
NORTHERLY FLOW OF 15 KT OR LESS IS EXPECTED ON THE WATERS TODAY. THE
PRESSURE GRADIENT IS EXPECTED TO BEGIN TIGHTENING TONIGHT AS LOW
PRESSURE OFF THE SE COAST. WINDS WILL SHIFT TO THE NE WITH SUSTAINED
SPEEDS OF 10 TO 15 KT...AND GUSTS TO AROUND 20 KT.

HIGH PRESSURE OVER NEW ENGLAND AND A COASTAL LOW MOVING OFF CAPE
HATTERAS MONDAY BRINGS NELY FLOW. A SMALL CRAFT ADVISORY IN EFFECT
FOR MONDAY /WINDS AROUND 20 KT/ FOR ALL WATERS EXCEPT UPPER TIDAL
POTOMAC /WILL HAVE TO MONITOR INLAND EXTENT OF STRONGER WINDS/.
WINDS BECOME MORE NLY MONDAY NIGHT WITH THE SMALL CRAFT ADVISORY
POSSIBLY NEEDING EXTENSION. SWLY FLOW AHEAD OF THE NEXT FRONT
WEDNESDAY. ONE OR MORE FROPAS LATER WEDNESDAY THROUGH FRIDAY TO
BRING WLY FLOW...SOME PRECIP AND COLDER AIR.

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST MONDAY
     FOR ANZ530534-537543.

LISTEMAA/BAJ